Method and means for recording and reproducing displacements



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Patented Feb. 17, 1953 UNITED STATES PATENT OFFICE METHOD AND MEANS FOR RECORDING AND REPRODUCING DISPLACEMENTS 31 Claims. 1

This invention relates to systems 101' the control of the displacements of various members along preselected paths or in preselected sequence and particularly to the controlled displacement of members used in the fabricating or processing of various materials.

The invention still more particularly relates to the automatic control of a machine to perform a cycle of operation during which the tool and material being machined or otherwise fabricated are moved relative to each other through a series of predetermined movements in a preselected sequence.

An object ofe invention is to control the different motio f work-to-tool or tool-to-work members of lab c ing machines so that the material being fabricated will be shaped, cut or otherwise formed or worked in exact duplication of a two or three-dimensional shape or body.

Another object is to simultaneously resolve the complicated movements of machine tool cycles into separate displacements lying in a system of coordinates and to separately impress the magnitude of each displacement on a control record which can be used to reproduce the original component movements.

Yet another object of this invention is to cause a lane or track, extending substantially along the length of a control record such as a reel of tape or film, to be displaced at right angles to the length of the control member in a direction and amount identical to the magnitude and direction of displacement of a machine-tool element such as a lathe-carriage or slide.

Still another object of the invention is the automatic control of valves, gates, feeders, burners and similar devices whereby control-elements of said devices are displaced in a preselected sequential manner to cause desired physical or chemical changes to take place in a material or substance in a desired chronological order.

Another object of the invention is to allow the timing of relative movements, between the work and tool supports of a machine-tool or other fabricating device, defining a complicated displacement of a control-record.

Yet another obiect is to provide an automatic control system which allows the complete stoppage of the fabricating machine at any point in a complicated cycle, necessitated by tool --cyclc-, to be instantaneously adjusted by manual or automatic means by controlling the rate of breakage or other cause, without any loss of cyclic control or accuracy due to time discontinuity.

Yet another object of this invention is to provide an automatic control system which allows an operator to substantially instantaneously cause the successive plural movements of work and tool supporting-members of a fabricating machine, which define a complicated fabricating cycle, to be reversed in direction and succession by merely reversing the direction that a control-record is normally displaced.

Another object is to provide a control system for a fabricating-machine in which the use of cams, templates and similar displacement-constraining-members are entirely eliminated in causing work and tool supporting-members to be displaced as they define a complicated fabricating-machine cycle.

Another object of the invention is the complete elimination of templates, forms and other contour-controlling members in the automatic control of complicated machine-tool cycles, thus allowing the overall physical dimensions of contouring-machines to be reduced or, under certain conditions, saving valuable floor space in fabricating shops.

Yet another object is to simultaneously measure and record the displacement of a stylus, template-follower or similar member in relation to the two normal axes of a two-dimensional Cartesian coordinate system.

Another object is to simultaneously measure and record the magnitude of the displacements of each successive position, occupied by a point traversing a spatial path, relative to the normal axes of a three-dimensional Cartesian coordinate system.

Still another object is to continuously measure the successive displacements of a point in relation to the normal axes of a three-dimensional Cartesian coordinate system and to simultaneously record the direction and magnitude of each of the displacements on separate flux-transmissive lanes or tracks impressed along the length of a motion-picture type film or similar control record.

Another object is the provision of a control system, adapted to automatically define complicated machine-tool cycles, governed by a control-record which, in many instances, may be completely prepared in a few moments and at an extremely low cost.

Another object of this invention is to provide a control-record, no larger in many instances than a reel of 16 mm. motion-picture film which is capable of completely controlling complicated machine-tool cycles lasting upward to an hour or more.

Another object is to provide a control-system allowing a certain, complicated machine-tool cycle of a machine-tool to be changed in a few seconds to a completely different cycle by merely substituting one control-record for another.

Another object of the invention is to provide a system of permanently recording linear or angular displacements in which the recording takes the form of equidistant, parallel, flux-transmissive lanes continuously impressed longitudinally to the length of a control record such as motionpicture type photographic film.

A further object is to provide a species of fluxgate consisting of a control-record and a displacement-measuring member whose coaction continuously controls flux-magnitude.

Another object is to continually govern the degree of opening of separate flux-gates in response to the displacements of recorded fiuxtransmissive channels or lanes perpendicular to their lengths so that the tool and work-supports of a machine tool are moved relative to one another through a series of movements and in a predetermined sequence in response to the magnitudes of flux being continually governed by the flux-gates from instant to instant.

Another object is to provide a novel control system adapted to define complicated machinetool cycles, involving relative motions, between the work and tool supports of a machine-tool along a plurality of paths. in response to the degree of openings of a plurality of flux valves controlled from instant to instant by a controlrecord.

Another object of this invention is to impress parallel flux-transmissive tracks along the length of a control-record while simultaneously causing displacement of the tracks perpendicular to the length of the control records length in an amount and direction proportional to the movement of a displacement-measuring member.

Yet another object is to provide a very simple control system which is preeminently suited to control the rate and direction of rotation of large power-elements such as direct-current motors,

alternating-current motors, hydraulic-motors,

hydraulic and pneumatic-cylinders, variable speed-reducers, turbines and the like, which are used to power control displacements between the tool and work supports of a fabricating-machine as they define a complicated fabricating-cycle.

Still another object is to provide a system whose control record, suchas a. motion-picture type film, has such a low rate of linear-displacement that, in many instances, the displacement of the control-record is only four or five times that of work and tool supporting members of a machinetool, thus makin for low cost and long life of the control record.

Another object is to provide an automatic cyclic control system for machine-tools which allows absolutely continuous, stepless displacements to be imparted to the various work and tool supports, as they define a complicated two or threedimensional, displacement-cycle, thus eliminating vibration to the machine-tool due to discontinuous displacement and producing finely-finished, stepless contour or surfaces in the work being fabricated.

Another object of the invention is to continuously and simultaneously control the rate and direction of displacements of one or more machine-tool slidable-members through a predetermined operational cycle in response to flux-variations continuously governed by the lateral displacement of flux-transmissive lanes impressed longitudinally on a control-record.

Another object of the invention is to represent each of the three Cartesian coordinates of any point on the enclosing surface of a three-dimensional object by imparting separate, perpendicular displacements to a set of recorded fluxtransmissive channels which, when reproduced, can accurately and simultaneously position a member in automatic response to the recorded perpendicular displacements.

Another object of the invention is to continuously represent the movement of a point traversing a spatial path by continuously representing each of the three Cartesian coordinates as a separate perpendicular displacement of fluxtransmissive channels which, when reproduced, will control the movement of a member in exact reproduction of the spatial path in response to the perpendicular displacements of the channels.

Another object is to accurately control the automatic displacement of work and tool supporting members of fabricating-machines through a complicated cycle by the continuous regulation of fluid, magnetic or electromagnetic fiux, responsive to the displacement of flux-transmissive channels impressed upon and perpendicular to the direction of movement of a control-member.

Still another object is to translate the configurations of two-dimensional outlines, shapes, forms or templates into recorded displacements of flux-transmissive channels which, upon reproduction, govern fiuid, magnetic or electromagnetic flux in response to the direction and magnitude of the reproduced displacements to accurately govern the movement of work and tool supporting members through a spatial path identical to the configuration of the outline.

Still another object of the invention is to translate the configurations or surfaces of two or three-dimensional outlines or solids into a series of recorded displacements, which upon reproduction, can control the relative displacements of machine-tool work and tool supports to pass through movements which, as desired, are either a magnification or reduction of the displacements of the original outline or solid.

In the drawings:

Figure 1 illustrates one embodiment of a displacement-recorder in its simplest form.

Figure 2 is an elevation of Figure 1.

Figure 3 is an enlarged cross-section taken through Figure 1.

Figure 4 is cross-section taken through Figure 1.

Figure 5 is a cross-section through one species of control-record.

Figure 6 is a schematic drawing illustrating a certain processing of one species of control record.

Figure '7 is a view taken in plan of one species oi Z-dimensional displacement-recorder.

Figure 8 is an elevation of Figure '7.

Figure 9 is another elevation of Figure 7.

Figure 10 illustrates in plan some of the essentials of the displacement-recorder illustrated by Figure 7.

Figure 11 illustrates the optical system used by the recorder shown in Figure '7.

Figure 12 illustrates in elevation certain elements shown in plan in Figure 10.

Figure 13 is another elevation of Figure 10.

Figure 14 is a perspective of one species of three dimensional displacement-recorder.

Figure 15 illustrates in large scale certain elements used in the device shown in Figure 14.

Figure 16 shows the optical system used in the device illustrated by Figure 14.

Figure 17 is an illustration of a section of control record.

Figure 18 is yet another illustration of the record shown in Figure 1'7.

Figure l9'is a plan view of a fabricating device whose two-dimensional displacements are automatically controlled by the instant invention.

Figure 20 is an elevation of Figure 19.

Figure 21 is another elevation of Figure 19.

Figure 22 illustrates certain elements essential to the operation of the fabricating device illustrated by Figure 19.

Figure 28 is a schematic drawing of an electronic amplifier used by'the device illustrated by Figure 19 and also used in several other species of the invention.

Figure 24 is a large-scale cross-section taken through certain elements of the device illustrated by Figure 19.

Figure 25 is a schematic illustration in largescale of a section of a control record under certain conditions.

Figure 26 is still another view of the control record illustrated by Figure 25.

Figure 27 is a schematic outline of one type of servo-mechanism.

Figure 28 is a schematic illustration of a second type of servo-mechanism.

Figure 29 illustrates a third species of servomechanism.

Figure 30 illustrates a fourth species of servomechanism.

Figure 31 illustrates a disc utilized by the device illustrated by Figure 27.

Figure 32 illustrates a member used by the system shown in Figure 28.

Figure 33 illustrates certain elements used in conjunction with the servo-mechanism shown in Figure 40.

Figure 34 is a cross-section taken through certain elements illustrated by Figure 33.

Figure 35 is another view of the devices illustrated by Figure 33.

Figure 36 is a graph which is intended to show the amplitude of certain voltages used in the servo-mechanism system illustrated by Figure 40.

Figure 37 illustrates the relative positioning between a certain flux pick-up and one species of control-record.

Figure 38 is another illustration showing the elements, illustrated by Figure 37 in a different relative position.

Figure 39 is another illustration of the elements shown in Figures 37 and 38.

Figure 40 illustrates a fifth species of servomechanism used in conjunction with an enginelathe.

Figure 41 shows a section of control-record used in conjunction with a certain speciesof pneumatic pickup.

Figure 42 is a cross-section taken through Figure 41.

Figure 43 is also a cross-section taken throug Figure 41.

Figure 44 illustrates one species of pneumatic controlled servo-mechanism.

Figure 45 illustrates a control system using a circular control disc upon which certain flux transmissive lanes have been impressed and which, upon reproduction are capable of controlling valves, louvers and similar members in a sequential manner.

Figure 46 illustrates certain details of the control device illustrated by Figure 45.

Figure 1 illustrates a displacement-recorder which may be used to continuously measure a single, linear displacement and cause the direction and magnitude of the displacement to be permanently recorded on a control-record. A meter-bar i is slidably supported by the two bearings, 2 and 3. The right-hand end of the meter-bar terminates in a dependent stylus 4. The cutter-bar is prevented from rotating by a key way (not shown) extending along its length and a key (not shown) integral to one Of the bearings.

The meter-bar is preferably made from steel, preferably having a substantial chrome-plated skin for wear-resistance. A plurality of identical cutting-teeth 5, extend substantially along the length of the meter-bar l which may have the rack-form illustrated in large scale, in Figure 3 or may be similar to the basic racks of the 14 /2 degree or 20 degree full-depth involute or other system. Figure 4 is a cross-section through the meter-bar, and clearly illustrates that each of the cutting-teeth 5, are shaped similarly to planar or shaper cutting-tools. The pitch of the cutting-teeth is constant and will be taken to be, for purposes of illustration, exactly 25 teeth per inch.

A strip of transparent material, preferably a plastic which is a polymerized derivative of methacrylic acid such as Lucite or Plexiglas, serves as a control-record 6, Figures 1, 2, 3, 4 and 5. The width of this control-record will be taken to be .500 wide, its thickness .040", while its length may be ten, a hundred or more feet in length, dependent upon the length of the cycle of linear-displacements of the stylus 4.

The control-record 6, is continuously displaced perpendicular to the length of the meter-bar and in the direction indicated by the arrow, Figure 1. The rate of linear-displacement is held constant by a control-record driving means which, although not shown, will be understood to be similar to the reel-drive of a motion-picture, film-reeling device.

The rate of displacement of the control-record should be held at preferably 5 times the highest rate at which the stylus 4 is moved. Therefore. the control-record will be constantly moved at the rate of 50 inches per minute if the maximum rate of displacement of the stylus does not exceed 10 inches per minute.

The plastic strip, constituting the controlrecord, is continuously and positively drawn against the cutting teeth 5, integral with the meter-bar l, causing a plurality of identical,

equidistant grooves to be simultaneously cut on one surface of the strip. These grooves will be generated in exact parallelism .with the edges of the plastic-strip at the instants when the meter- 7 or cut grooves to be displaced or skewed towards the right-hand edge of the control-record while opposite displacement of the meter-bar causes the grooves to be oppositely displaced towards the left-hand edge of the control-record.

Any rate of displacement of the meter bar produces a corresponding deflection to be imparted to the grooves so that the direction and magnitude of angular displacement of the grooves, measured in relation to the length of the control-record, becomes a precise record of the rate and direction of movement of the stylus and. meter-bar from instant to instant.

Figure 6 illustrates, in a schematic manner, further processing of the plastic-strip after having the equidistant grooves generated along its length by the cutting action of the meter-bar. As indicated, the plastic-strip, constituting the control-record, is drawn from right to left. As the strip is continuously advanced under the hopper I, finely comminuted pigment is delivered by gravity from the hopper to the grooved-surface of the plastic-strip, completely filling the grooves. The strip is then advanced to a stationary plow 8, which shears off any excess pigment lying on the ungrooved surfaces of the plastic strip. The grooves are thus filled with dense, opaque powder while the intervening lands or surfaces, lying between the powder-filled grooves, are perfectly clean to offer maximum transmission to light-flux.

The last operation is to continuously apply a very thin, tough, transparent plastic-strip 9, to the upper-surface of the control-record and thus permanently seal the opaque pigment in the grooves. Cellophane" tape having one tacky surface may be used for this purpose. As indicated, the thin protecting tape may be applied under pressure by the action of a presser-roll 3a, bearing downwardly towards the plate Ill, which slidably supports the control record as it is being grooved.

Figures 7, 8 and 9 illustrate one species of twodimensional displacement-recorder. A fiat metal base I2, whose upper surface I1, is ground to afford a perfect plane-surface, has two, upwardly extending, integral brackets I3 and a, which serve as rigid supports to a longitudinal-support I4. This longitudinal-support is preferably a. seamless steel tube of circular cross-section. Its surface is highly finished and polished and should have a high degree of wear-resistance. The longitudinal-support is so positioned that its axis is in exact parallelism with the plane-surface of the base I2.

A boom I6, also preferably of the same material, finish and cross-section as the longitudinalsupport I4, extends outwardly from that support. The axis of the boom is always maintained at an angle of exactly 90 degrees to the axis of the longitudinal-support and in precise parallelism with the plane-surface I! of the base I2. One end of the boom is integrally fastened to a T-member I8. The horizontal section of the T is carefully bored and fitted with two sleeves of bronze or similar bearing material which serve as substantially frictionless supports to the booms displacement along the length of the longitudinal-support. A key-way extending the length of the longitudinal-support and a cooperating key, integral with the T I8, may be provided to maintain exact parallelism between the axis of the boom and the plane-surface II.

A pulley I9, preferably journaled on ball-bearings, is rotatably supported at the outward end or the boom. Two smaller pulleys 20 and 2|, similarly journaled, are mounted on the T-member II. The three pulleys are in the same horizontal plane. A flexible, lateral meter-ribbon 22, in the form of an endless-belt, is supported by the three pulleys. The meter-ribbon is preferably made of Invar, selected for its extremely low co-eilicient of thermal-expansion. The dimensions of the ribbon will be assumed to be, for purposes of description, some .250 inch wide by .005 inch thick. The metal ribbon is kept in continuous tension by a compression spring carried inside the boom which constantly presses the support of the large pulley I9 in a direction parallel to the axis of the boom and in a direction opposite to the T I8. A cross-head I3, is slidably supported by the boom. A key and key-way, similar to the key and key-way in the longitudinal support and T I8, are used to prevent rotation of the cross-head which is bored and fitted with bronze bearings to allow frictionless displacement of the cross-head along the length of the boom. A stylus 24, extends downwardly from a bracket 23a integral with the cross-head. The stylus is rigidly clamped in a vertical position in the bracket 23a. The stylus may either be equipt with a small roller or be brought to a sharp, hardened-point as shown in Figures 7 and 8.

A small, upwardly-extending bracket 34, integral with the cross-head, is securely fastened to one strand of the lateral meter-ribbon. It should be noted, due to the position of the centers of the pulleys I9 and 2|, that the strand, fastened to the bracket 34, is in exact parallelism with the axis of the boom.

An upward-extending bracket 25, Figures 8, 9, l2 and 13 and two spaced brackets 26 and 21, all integral with the T-member I8, serve as supports for an upper storage-reel 2B and a lower drive-reel 29. These reels may be considered identical to reels upon which motion-picture film is wound. The reels are mounted on conventional anti-friction bearings. The lower reel is preferably driven by means of a small alternatingcurrent motor 30, which serves to continuously drive the film 35, downwardly as it is unreeled from the storage-reel.

A longitudinal meter-ribbon 3|, made of Invar is rigidly supported in parallelism with the axis of the longitudinal-support I4. Two supports 32 and 33, integral with the brackets I3 and I411. serve to rigidly support the meter-ribbon 3]. A tensioning device, such as a threaded take-up in one of the supports 32 or 33, may be provided to hold the meter-ribbon in tension, Like the lateral meter-ribbon, the longitudinal meter ribbon will be assumed to be .005" thick by .250" wide.

A series of equidistant apertures 35, extend along the center of the longitudinal meter-ribbon 3 I. Identical apertures are also cut through that section of the lateral meter-ribbon 22, which passes across the face of the film 36, as the cross-head is moved through its maximum displacement from one end of the boom to the other.

The pitch of the apertures 35, will, for purposes of description, be assumed to be exactly .040" while their dimensions are precisely .020 by .020". These square apertures should be preferably punched through the Invar ribbon stock. Their spacing should be very accurately maintained since the accuracy of the complete displacement-recorder is dependent upon theirlocationing. Also it is essential that the edges of each aperture be completely free of burrs or roughness and that their dimensions be maintained within very close limits.

A film-support 31, of the shape outlined by Figure 13, preferably polished stainless-steel of .005" to .008" thickness, serves as a slidable support for the downwardly advanced photographicfilm 36. Two staggered apertures, 38 and 39, Figure 12, are cut through the film-support 31. Aperture 38, is so positioned that it is in exact register with the plural apertures cut through the longitudinal meter-ribbon 3| while aperture 39 is similarly positioned in relation to the lateral meter-ribbon 22. Each aperture 38 and 39, is exactly .020" wide by .160 long.

Figure 11 illustrates an optical system used in conjunction with the displacement-recorder illustrated by Figures '7 to 13. The fiux from two filament-type, projection-lamps 40 and 4|, preferably receiving their energy from a direct-current source, is collected by the two, similar conthrough the film-support 3'1. It will be understood that the meter-ribbon apertures 35, have been purposely shown out of scale in Figures 12 and 13 for clarity of illustration. Figure 11 lllustrates the fact that the lateral and longitudinal meter-ribbons, 22 and 3|, are maintained so that they lightly bear against the smooth, polished inner-surface of the film-support 31. Since the surfaces of the Invar meter-ribbons are also very smooth, practically no friction results i when they are horizontally-displaced during displacement-recording operations. The film-support serves as a means for definitely separating the ribbons from the emulsive surface of the film by .005" or by whatever thickness the film-supv port may be.

Functioning of the displacement recorder, whose various essential elements have been just discussed, will now be described. A template 50, of the outline indicated in Figure 7, is temporarily bolted or otherwise rigidly fastened to the plane-surface ll, of the displacement recorder base I2. The template may be made of fibre, plywood, plastic or metal dependent upon the accuracy required. For the highest type of accuracy a metal template some a; or of an inch thick should be preferably used.

The storage reel 28, is loaded with motionpicture type, photographic-film 36. The film, which is especially selected for the high resolving power of its emulsion, is downwardly displaced in response to the rotation of the motor 30, at a constant linear-rate approximately 5 times greater than the highest rate at which the stylus is manually moved about the configuration of the template 50. Therefore, if the maximum rate, at which stylus displacement occurs is per minute, the rate of displacement of the film 36 would be 100" per minute, while a stylus displacement of 100" per minute would call for the film to be moved 500" per minute, etc.

The cross-head would be manually moved outwardly from the position occupied in Figure 7, while the boom would be simultaneously displaced from left to right until the tip of the 10 stylus 24, contacted the corner of the template 50, at A which is the starting point of the displacement-recording cycle. The motor 30, is energized to continuously draw the photographiclm downward at a constant rate which, for purposes of description, will be assumed to be per m nute. The filament: of. the lamps 40 and 41, Figure 11 are simultaneously lighted.

The stylus 24 is manually displaced from points A" to B" along the templates edge which is parallel to the longitudinal support l4. Since the complete recording device, consisting of the optical system, the reels, the motor and the film, is mounted on the T-member l8, the movement of the boom causes the film recorder to be moved from left to right.

Since the pitch of the apertures is .040", exactly 25 apertures 35, will pass at right angles to the length of the film for each inch of the boom's displacement. The movement of the apertures will be from right to left (opposite to the direction of the booms movement) in relation -to the film. If the rate of film movement is exactly 100 inches per minute, the maximum rate, of stylus displacement, as stated, preferably would be limited to one-fifth of the film speed or 20" per minute. i

As each aperture 35, cut along the length of the longitudinal meter-ribbon 3|, comes into the zone bounded by the edges of the aperture 38, Figure 12, light-flux, collected by the condensing-lenses 42 and 43, is caused to fall upon the light-sensitive surface of the downwardlymoving photographic-film. Since the length of this aperture is, as stated .160" and the pitch of the apertures 35, is .040", exactly 4 of these apertures will be contained within the boundary edges of aperture 38, at any instant.

In this manner four, parallel, equidistant pencils of light, each .020" in cross-section are caused to continuously trace the displacement of the longitudinal meter-ribbon on the photosensitive surface of the film 36. Each of the 4 traces, photographed on the film, are separated by unexposed areas whose widths are identical to the .020" wide exposed traces or channels.

The stylus, upon being displaced to point B" on the template 50, Figure 7, is displaced towards point C. Longitudinal movement of the boom will be zero, while the stylus-head 23, integral with the stylus, will be displaced towards the longitudinal support I4, causing movement of the strands of the lateral meter-ribbon in a clock-wise direction when viewed in plan. In this manner the lateral meter-ribbon 22, will be displaced from right to left across the film 36, at a rate identical to the rate of displacement of the stylus as it is moved along the edge of the template from points B to C.

The lateral meter-ribbon is used to continuously photographically impress four .020" wide lanes upon a separate area extending along the length of the photographic film, in a manner identical to the means by which longitudinal displacements are continuously and simultaneously recorded.

The edge of the template 50, Figure 7, between points "0 and "D extends at an angle of 45 to the axis of the boom l6, and the longitudinal support I4. As the stylus 24, is moved along this edge it is longitudinally displaced parallel to the axis of the support l4, and laterally displaced parallel to the axis of the boom IS. The direction of the longitudinal displacement of the stylus is from right to left while its lateral displacement is towards the longitudinal-support I4. These longitudinal and lateral displacements are simultaneously recorded by causing perpendicular displacement to be imparted to two separate groups of parallel, photographed traces by amounts and in directions which are exact indices of the longitudinal and lateral displacements of the stylus.

Figures 17 and 18 illustrate sections of the film 36, sections of the longitudinal and lateral meter ribbons 22 and 3|, and the film support 31. The positions of the above elements have been rotated through 90 in relation to their positions illustrated by Figure 12. These figures illustrate the displacement of the traces which have been exposed to the luminosity from the lamps 40 and 4 I. The exposed areas are illustrated by cross-hatching. Figure 1'? illustrates that a stationary condition of the longitudinal meter-ribbon has caused zero perpendicular displacement to be imparted to the exposed traces, lying in the longitudinallane of the film. It further indicates that the lateral-control traces on the film have been displaced from right to left. Figure 18 indicates that the longitudinal meter-ribbon has been displaced from right to left while the lateral meterribbon has been displaced from left to right.

From the description of the operation of the device it will be seen its use enables an operator to continuously measure each successive point, occupied by a stylus as it is manually moved about the configuration of a complex template, in relation to the two normal axes of a Cartesian coordinate-system while simultaneously recording the direction and magnitude of the longitudinal and lateral components. Methods and means for the play-back" of the film 36, to initiate the control of large power elements, whose rates and directions of movement, control the displacements of the work and tool supports of fabrieating machines, will now be illustrated and described.

Figures 19, and 21 show a species of twodimensional displacement-reproducer which is specifically designed to accurately control the movement of a gas cutting torch in reproduction of the outline of the template 50, Figure 7, or any other desired outline. As will be later shown, the movement of the cutting torch is responsive to the play-back of a two-dimensional control record such as is illustrated by Figures 17 and 18. The displacement-reproducer, Figures 19 and 20 and 21 are so similar that with minor modifications the displacement-recorder can be used interchangeably as a displacement-reproducer. The modifications are: the addition to the displacement-recorder, of two gear-racks, two motor-driven speed-reducer units and two electronic amplifiers and the substitution of a gas cutting torch for the stylus 24, Figure 8. The gearrack I06, Figure 20, extends, integral with and along the length of the boom I05 and is so positioned that the faces of the teeth are vertical. Figure 24 is a cross-section taken through the boom, gear-rack and cross-head I I I. A gear rack I01, is similarily afixed to the underside of the longitudinal member I08; A small, motor-driven speed-reducer I05, is rigidly fastened to a dependent bracket IIO, Figure 24, which is integral to a cross-head III. A pinion II2, whose pitch is identical to that of the gear-rack, is pressfitted on the slow-speed shaft II3, of the speedreducer unit I03. The teeth of pinion H2, mesh with the teeth of the gear-rack I06. An identical speed-reducer unit H4, is rigidly supported by the T-member I3, in a manner similar to the support of the speed-reducer unit I09, shown by Figure 24. Figure 22 illustrates that the same optical elements, shown in Figure 11, are used by the displacement-reproducer. Lamps 40 and M, Figure 11 although not shown in Figure 22 are also included.

The light-flux from the dual, condensing-lens systems, consisting of lenses 42, 43, 44 and 45, after being stopped-down by the apertures 41 and 43, cut through the stop 46, is projected through the multiple apertures 35, punched along the lengths of the longitudinal and lateral meterribbons 3| and 22, then passes through the apertures 38 and 39, in the film-support 31, to be finally projected through the transparent traces of the control-film I60, upon the light-sensitive areas of the two photo-tubes I20 and I2I.

Figure 23 is a circuit-diagram of an electronicamplifler used to amplify the feeble currents of one of the photo-tubes I20 or I 2I and to control the direction and rate of angular displacement of the rotor I23, of a small reversing inductionmotor with wound shaded-poles, such as are commonly used for driving valves, dampers or recording devices. The input to the motor-field I24, which is alternating-current, preferably of a standard frequency such as 50 or cycles, runs as high as 25 watts at 115 volts. The motorspeed may be varied over a range of 4:1 in either direction, or a differential action may be obtained, the motor speed and direction varying according to the difference in the excitation of the shading-poles I25 and I26.

Each of the motor shading-pole windings, is connected to the primary I21 or I23 of a transformer, the secondary I33 or I34, of which is connected to the plate-filament circuit of a vacuum tube I29 or I30. The tube grid-circuits may be arranged in a number of ways, one of which is shown in Figure 23. The only requirement of the grid-input is that suflicient voltage be supplied to swing the grids from cut-off up to approximately zero-voltage. The field I24, of the motor is continuously excited from the alternating-current line I3I, I32, and the wound shading poles I25 and I26, acting as transformer secondaries, have about 25 volts induced in them. This voltage is applied to the transformers and these, being of a high step-up ratio develop the platevoltage for the vacuum tubes I29, I30 which are preferably a type 471' triode connected tube. If the grids are normally biased to cut-01f, no plate current flows and the primaries I21, I28 of the transformers are of such a high impedance that insufilcient current is drawn through the shadingpoles I25, I 26 to produce rotation of the rotor I23. When the grid-voltage conditions are changed so that one of the tubes is conducting, the primary-current, drawn from the shadingpole by the tube-load on the transformer, is large enough to cause full-speed operation of the motor in the desired direction. In normal use, such a motor is designed to be operated by short-circuiting one or the other of the shading-poles I25, I26. The plate-resistance of the tube, reflected into the primary-circuit by the transformer is low enough to constitute an effectual short-circuit of the shading-winding effecting the motor's opera ion.

Due to the poor regulation of the shading-pole winding, the voltage drops to about 6 volts when full current of 0.30 ampere is carried. This reduces the plate-voltage to about volts and necessitates a slightly greater grid-voltage swing to obtain the desired plate-current of 20 milli- I sensitive, a one amperes. The large drop in plate-voltage with current allows the use of higher than normal plate-voltages during the time the tube carries no current, without at the same time producing undue tube heating. The transformers have low-resistance primaries and are designed for low-magnetizing current. Several types of microphone to grid transformers give very good results. The main requirement is a low resistance primary, so that the effect of the circuit resistance will be largely determined by the reflected tube load and allow a large value of current to flow in the shading-pole circuit with the tube conducting. With the tube non-conducting, the impedance of the transformer must be high enough to prevent rotation of the motor-rotor I23 by the transformer magnetizing-current, flowing through the shading-coil.

The circuit, illustrated by Figure 23, is very volt change in phototube-output being sufficient to change the motor from full speed in one direction to full speed in the other. At some value of voltage on the grid of the tube I36, which is preferably a type 57," the platecurrents of the two type 47 tubes will be equal and, the excitation of the two shading-poles I25 and I26 being equal, the motor will be at rest. If the 57 grid-voltage is changed slightly, the grid-voltages of the two tubes I29 and IE0, are changed differentially and the current in oneshading pole is increased, the other decreased. The motor then rotates slowly in the direction of the stronger shading-pole. By larger changes of 57 tube grid-voltage, a greater speed may be attained or by a grid-voltage change in the opposite direction the motor may be reversed. A considerable change in sensitivity can be covered by changing the values of the plate-resistors I3! and I38 in the type 57 tube plate-circuit although a value of 250,000 ohms will be generally found to be satisfactory.

Two, reversing, induction, wound shaded-pole motors, whose control have been described and which are schematically illustrated in Figure 23, are separately mounted in the housing of the gear-reducer I09, and gear-reducer H4. The rotor-shaft of each motor is direct-connected to a gear-type speed-reducer, housed in each of the speed-reducer units I09 and II4. The voltage output of photo-tube I20, which receives its controlled luminosity from a longitudinal control lane, photographed along the length of the control film IE0, is used to control the functioning of an amplifier similar to the one shown in Figure 23. The output of the photo-tube I2I, is similarly used to control the functioning of a second similar amplifier in response to light variations controlled by a lateral control lane also impressed along the length of the control-record I60. The voltage-output of the photo-tube I20, controls the direction and rate of rotation of the pinion I I2, mounted on the slow-speed shaft I I3, of the speed-reducer I 09, Figure 24. The voltage-output of the photo-tube I2I similarly controls the rotation of the second pinion (not shown), mounted integral to the slow-speed shaft of an identical speed-reducer unit I III. Since the teeth of the pinions, driven by the speed-reducers III-9 and IIII, are in mesh respectively with the teeth of the racks I06 and I01, movement of the boom I05, and movement of the cross-head III, will be governed at all times by the magnitude of light-flux falling upon the photo-tubes I25 and I 2| respectively.

Figures 25 and 26 illustrate a section of a con- 14 trol-film I 50, and a broken length of meter-ribhon I5I Alternate opaque-tracks I 53 and transparent-traces I 54, which, collectively, make up a single control-lane are shown. In Figure 20, the opaque sections of the film have been crosshatched for clarity. The directionof movement of the film I 50, Figure 25, is downward in a vertical direction. The movement of the meter-ribbon I5I, is perpendicular to the direction of the film's movement. It will be assumed that the widths of the transparent traces I56, are .020" that the dimensions of the apertures are .020" x .020" and that the apertures are located along the length of the meter-ribbon at a pitch of exactly .040". These figures are intended to illustrate that exactly one-half of each apertures area is in register with the surface of a transparent trace. When this condition exists the width of the effective light-transmissive area of each aperture is reduced from .020 x .020" to .010" x .020". This relative position of the apertures I 52, to the transparent traces $54, is the control point position of the flux-gate illustrated by Figures 25 and 26. The use of the term control point in this disclosure is intended to describe the above relative position of the apertures with their coacting traces. Another way of describing the control point is, that position of the meter-ribbon in relation to the traces in which each aperture is exactly bisected by the edge of a transparent trace. In this manner when a flux gate is at its control point the areas of its flux-passages are at 50% of their maximum.

A right-hand movement of the meter-ribbon I5 I, from the control-point position, as illustrated by Figures 25 and 26, through a distance of 0.10" will cause the apertures I52, to coincide with the transparent traces I54. A similar .010" movement of the meter-ribbon I5I, but in a lefthand direction from the control-point position, causes the apertures to register exactly with the .020 wide opaque areas I53, which separate the transparent traces I54. In the former case maximum light-flux is projected through the apertures and transparent traces while in the latter case zero light-flux is valved through the apertures and the opaque areas. Since a .010" righthand displacement of the meter-ribbon from the control-point position of the flux gate, Figures 25 and 26, causes a increase in the lightfiux valved by the flux gate, it will be seen that any movement of the metal-ribbon I5I to the right of the control-point position causes a decrease in the magnitude of the valved light-flux in exact proportion to the meter-ribbons movement. Therefore, a .001" right-hand displacement of the meter-ribbon from the control-point=l0% increase in light-flux; a .003" displacement=a 30% light increase; a .0005" displacement=a 5% light increase etc., etc. Conversely any displacement of the meter-ribbon to the left of its control-point position, causes a corresponding decrease in the light-flux projected through and regulated by the flux-gate, Figures 25 and 26. There are some 14 or more transparent traces I54, Figures 25 and 26, photographed on the film I50, which with the opaque lanes I53, constitute a single controllane. There are only 4 traces on the longitudinal control lane and a similar number on the lateral control lane which are jointly impressed along the length of the control-record I60, Figures 19, 21 and 22. However, the functioning of the flux-gate, illustrated by Figures 25 and 26, is identical to the operation of the longitudinal and lateral flux-gates used to control the gas-cutting torch, Figure! 19, 21 and 22.

Since longitudinal movement of the boom I55:

along the axes of the longitudinal member I08, Figures 19, 20, and 21 is controlled by rotation of the motor driven speed-reducer Ill, it will be seen that the controlled movement of the boom is continuously governed by the magnitude of the flux being valved from instant to instant by the longitudinal flux-gate. In a similar manner the amount of light, falling upon the photo-tube I2I, which is being continuously regulated by the lateral flux-gate, controls the rate and direction of lateral-movement of the cross-head III, along the axis of the boom I05.

The luminosities of the lamps and H are adjusted by manually-controlled rheostats (not shown) until the intensity of the light, falling upon the photo-tubes I20 and I2I, is such that the rotors of the two shaded-pole motors are stationary when their controlling longitudinal and lateral flux-gates are in their exact controlpoint positions. This adjustment, obviously, is made with a control-record I60, in place, and at rest upon the reel-driving mechanism, since the transparent traces, impressed on the record's surface, cooperate with the two meter-ribbons to constitute the two flux-gates. Upon the filmdriving motor 30, being energized, the control record ISO, is drawn downwardly at a uniform 5 rate. The flux-gates will remain in their controlpoint positions as long as the transparent traces are exactly parallel with the edges of the film upon which they are impressed.

Now assume that the transparent traces, constituting the lateral control lane, when viewed in the same position as Figure 12 (it being understood that the film-driving mechanism of the displacement recorder and reproducer are identical), are displaced slightly to the right in a direction perpendicular to the film's length. This movement of the traces in a right-hand direction, in relation to the cooperating apertures 35, cut in the lateral meter-ribbon 22, would cause (for purposes of description) more light to fall upon the photo-tube IZI. The rotor of the shadedpole motor, direct-connected to the speed reducer unit I09. Figures 20 and 24, would instantaneously respond to the increase in light-flux falling upon the photo-tube, and rotate in such a direction that the pinion H2, Figure 24, would be caused to rotate in a counter-clockwise direction. The cross-head III, Figures 19, 20 and 24 would immediately be displaced along the axis of the boom I05, away from the longitudinal member I08. This displacement of the crosshead would be instantly communicated to the lateral meter-ribbon 22, causing that section of the ribbon, in contact with the film support 31, Figure 22, to be drawn from left to right by an amount identical with the cross-heads displacement. In this manner, the apertures 35, cut in the lateral meter-ribbon 22, will be moved in the same direction as the displacement of the traces, perpendicular to the film's edges. If the rate of the meter-ribbon's displacement is not as great as the rate at which the traces are being displaced to the right, the effective areas of the apertures will be increased to permit still more light to fall u on the photo-tube I2I. This would be instantly reflected by a higher rate of rotation of the rotor of the motor, causing the cross-head to be moved at a higher speed towards the large-pulley end of the boom and causing the section of the meter-ribbon, in contact with III 16 the film-support 01, to be displaced at a higher velocity from left to right. The movement of the meter-ribbon would be accelerated until the rate of its displacement would exactly equal the rate of perpendicular displacement of the traces to the right.

If the angular displacement of the traces towards the right-hand edge of the control-film I60, gradually decreases until the traces are again parallel to the films edges, the amount of light, projected through the cooperating-apertures 35, will decrease in exact response to the change in the perpendicular displacement of the traces, until the shaded-pole motors rotor is brought to a standstill, when the control-point position of the flux-gate is again reached. Obviously, if the lateral traces are gradually deflected in a direction towards the left-hand edge of the control film or record I60, the intensity of the light falling upon the photo-tube I2I, would be less than the amount admitted by the flux gates control-point position. The electronic system would immediately respond to cause the motor to rotate in a direction opposite to that which it assumed when the traces were displaced to the right. This would, therefore, cause the pinion I I2, Figure 24, to be rotated in a. clock-wise direction (when viewed in plan) and thereby cause the cross-head III, to be displaced towards the longitudinalmember I08. Since the electronic system, illustrated by Figure 23, is so sensitive that a onevolt change in the output of the photo-tube I2I, will change the speed of the shaded-pole motor from full speed in One direction to full speed in the other, the increase or decrease of light-flux, continuously valved by the flux-gate, ha only to be a very few percent above or below the value of the light-flux admitted by the flux-gate when it is in its control-point position to obtain similar motor speed-regulation.

Movement of the boom I05, along the axis of the longitudinal member I08, is controlled in a manner identical with that used in the automatic displacement of the cross-head III, Figures 19, 20. The longitudinal traces are photographed along the longitudinal control-lane which lies parallel to the lateral control-lane. The longitudinal lane is adjacent to the left-hand edge of the control-record I60. Cooperation of the longitudinal traces with the apertures 05 cut along the length 01' the longitudinal meter-ribbon 5|, cause the intensity of the light-flux from lamp 40, Figure 11, to be continuously regulated before it falls upon the light-sensitive area of the phototube I20, Figure 22.

By the use of the displacement-reproducer it will be seen that the tip of the gas-cutting torch IN is caused, by the simultaneous controlled displacements of the boom I05 and the cross-head III, to be displaced along a spatial path lying in a single-plane, which is identical in configuration to the outline oi the template 50, Figure 7.

Figure 14 is a partial view taken in perspective, of the elements, essential to the operation of one species of three-dimensional displacement-recorder whose members are, in many respects, similar to the main members or the two-dimensional displacement-recorder just described. Therefore, although not shown, it will be understood the device illustrated by Figure 14, has a base and two upwardly-extending brackets similar to the base, Figure '7 and brackets I3 and Ila, to afford support to the longitudinal-member 60, whose axis is parallel to the horizontal plane-suror "Snychro-tie systems.

17 face of the base. An outwardly-extending boom 9|, slidably supports a cross-head 62, which is prevented from rotation about the boom by provision of a key-way 64, cut in the boom and a cooperating key, carried integral with the crosshead. The boom is slidably supported by the longitudinal-member. The axis of the boom is maintained parallel to the horizontal plane-surface of the base by means of a key secured to the T-end of the boom and sliding in the key-way 63, generated along the length of the longitudinal-member. A stylus 65, is slidably supported in a vertical position by the two brackets 61 and 69, integral with the stylus-head 92. The stylus may terminate at its lower end in a roller or a sharp hardened tip, as illustrated, and in a smooth spherical-knob at its upper end.

Three similar pinions separately mesh with three racks; pinion 69, meshing with the longitudinal-members rack 10, pinion 1|, meshing with the rack 12, generated along the boom's length, with the third pinion I9, meshing with the rack 14, out along the length of the stylus 95. For purposes of description it will be assumed that the pinions have 16 teeth of exactly .0625" circumferential pitch. Their three coacting racks 10, 12 and H, are of identical pitch. The three pinions, therefore, pass through exactly one revolution for each inch that the pinions are rolled along their cooperating racks, since 0625" x 16:1.000. Pinion 69, is integrally mounted on the rotor-shaft of a generator 15. The motor-shaft of generator 16. similarly mounts the pinion while pinion 13, is integral to the rotor-shaft of the generator 11.

The rotor of generator 15, is electrically connected to the rotor of motor 18, by three conductors 8|, 82 and 83, similar connection is made between the rotors of generator 16 and motor 19 by conductors 84, 85, and 86 while the rotors of generator I1 and motor 80, are connected through the leads 81, 88 and 89. The six stator-windings of the three generator and their coact ng motors are all energized with single-phase alternating-current of preferably a standard frequency from the same identical source. The representations of the two conductors. carrying this alternating-current are, for purposes of clarity, not

shown in Figure 14.

Each generator and its electrically-cooperating motor, constitutes a self-synchronous remotecontrolc commonly known as Selsyn," Autosyn These devices are so commonly used to accurately transmit angularmotion between two or more remote devices which cannot "be conveniently mechanically-interconnected, that it is not considered necessary to further describe their action. Sufiice it to say that, by the use of this type of remote-control device, it is possible to cause the discs 90, 9| and 92, separately mounted on each of the rotor shafts of the motors, to reproduce any angular displacement of their cooperatinggenerators rotor-shaft.

The disc 90, is mounted integral to the rotorshaft of the motor or Selsyn repeater 18, the disc 9|, is similarly mounted on the rotor-shaft of the motor or repeater I9, while the third disc 92, is likewise mounted on the rotor-shaft of the motor 80.

In this manner a 1.000" displacement of the boom 6|, parallel to the longitudinal-member 90, or parallel to the X--X axis of a three-dimensional Cartesian coordinate system, causes angu lar-displacement of the disc 90, through exactly 360. A similar linear displacement of the crosshead 62, along the booms length or parallel to the Y-Y axis of the three-dimensional coordinate system, causes a 360" rotation of the disc 9|. Movement of the stylus 65, parallel to the Z-Z axis of a three-dimensional Cartesian coordinate system through 1.000" will cause a 360 angular displacement to be imparted to the disc 92. Obviously, the linear-displacement of either the boom, the stylus-head or the stylus will cause an angular displacement to be imparted to the cooperating discs, in amounts and directions exactly proportional to the linear-displacements.

By the use of Selsyn or similar systems for electrically transmitting mechanical motion it is feasible to locate the repeaters or motors 18, I9 and and the discs 90, 9| and 92, many hundreds of feet, if desired, from the main mechanical elements of the three-dimensional displacem-ent-recorder, illustrated by Figure 14. In some installations the use of fiexible-shafting to acourately transmit rotation of the pinions 69, II and 13 to the discs 90, 9| and 92 may be substituted for the use of electrical Seisyn systems.

The three discs are identical and preferably made of thin optical glass or transparent plastic. One face of each disc is oqaqued by having a coat of aluminum, copper or silver evaporated upon its surface, although a coating of certain opaque lacquers or enamels may be used. Material of this masking-coat is removed either by mechanicalworking, etching, or by photo-engraving to form a three-thread spiral of the opaque masking coat. The configuration of the spiral 93, is clearly illustrated in Figure 15. The pitch of each spiral is such that it advances outwardly from the disc's center, a distance of exactly .1200" when displaced through 360 in a clock-wise direction. Since there are three spirals, the distance, measured radially between the centers of adjacent opaque spirals, is .040" while their widths are .020". The areas of the disc, lying between the spirals, are transparent and, therefore, light transmissive. The three motors 18, 19 and 90, and discs 90, 9| and 92 are preferably mounted in the staggered relationship to the stop-plate 94a and motion-picture type photographic-film 94, illustrated by Figure 14. Although not illustrated in the figure, it will be understood that the film-drive is similar to the drive illustrated in Figures 10, 12 and 13 and, therefore, consists of a storage reel, a drive reel, a drive-motor with speed-regulating control, to maintain a constancy of film movement, and a necessary lighttight enclosure for the enumerated elements.

Figure 15 illustrates a broken-section of the photographic-film 94, and a broken-section of the stop-plate 94a, as well as details of the disc 90, identical to the discs 9| and 92. Each of the discs is preferably separated from the plane-surface of the stop-plate by one or twothousandths of an inch. The stop-plate is similarly separated from the light-sensitive surface of the film 94. An aperture 95, Figure 15, is cut through the stop-plate. Two similar apertures, although not illustrated in Figure 14 are provided to cooperate with disc 9| and disc 92 in a manner identical to the aperture coacting with disc 90. The width of each aperture is preferably the same as the width of an opaque spiral or .020" while its length is .1200".

Figure 16 illustrates the light-system used in conjunction with disc 90. Discs 9| and 92 have identical individual systems. The Selsy repeater or motor I8, is shown with the disc 99, integrally mounted on one end of its rotor- 

